The following descriptions and examples are not admitted to be prior art by virtue of their inclusion within this section.
Certain optoelectronic packages include components that are mounted at an angle (i.e., a mounting angle) relative to other components or mounting surfaces in the optoelectronic package. One such angled component is a photodetector. The term photodetector generally refers to any type of radiation detector that detects electromagnetic radiation. One type of photodetector is a two-layer junction photodetector, or photodiode, which has a semiconductor p-n junction that produces electrical current under illumination with electromagnetic radiation. A photodetector may be used in a laser package (e.g., in an optical transmitter) to monitor light being emitted from a laser and coupled into an optical fiber. A photodetector may also be used in a photodetector package (e.g., in an optical receiver) to receive and detect light exiting an optical fiber.
In a laser package, for example, the photodetector is commonly provided in the same package as the laser to function as a check device to verify the proper operation of the laser. This photodetector is sometimes referred to as a “monitor photodetector” or “monitor photodiode,” due to its function in monitoring the output power of the laser. In such laser packages, a fiber may be mounted to receive the primary laser light output from a laser diode and a photodiode may be mounted to receive the small portion of light emitted from the back of the laser diode. This photodiode may be mounted at an intermediate angle between 0° and 90° relative to the emitted light because an angle of 0° may detect too little light and an angle of 90° may cause excessive back reflection. Likewise, a photodiode may be mounted at an angle within a photodetector package in a receiver so that the light output from the output end of the fiber is directed onto the active or light-receiving region of the surface of the photodiode.
One example of an optoelectronic package is a TO (transistor outline) can type package, which may be used to align and position the photodetector, laser, fiber, and/or related optical components. Other optical components may include collimation and coupling lenses, isolators, and the like to optically couple the laser or photodiode to the fiber. These components may be mounted in the TO can package (e.g., to the TO can post and/or header), and an optical fiber may be aligned with the components and coupled to the package (e.g., sometimes referred to as fiber pigtailing). As mentioned above, some of these components (e.g., the photodetector) may be mounted at a mounting angle (e.g., between 0° and 90° in the TO can package, while other components are not angled (i.e., a mounting angle of 0°).
To mount the components (e.g., laser diodes, photodiodes, lenses, and the like) in the proper locations with the desired mounting angles, the optoelectronic package may be first secured in a fixture. A pick and place machine may then precisely position the components in the appropriate mounting location within the package for bonding to the mounting surface. Mounting components at an angle using these machines presents unique challenges because the pick and place machines generally position components straight into the package (i.e., not at an intermediate mounting angle). Existing fixtures are configured to secure TO can packages and to angle the packages to allow certain components to be bonded at an intermediate mounting angle; however, these fixtures suffer from a number of drawbacks. In particular, some existing fixtures use a screw to provide angular adjustment to position the package at the desired angle, which is slow and creates problems at the production line. Existing fixtures also use a vacuum to hold the TO can package in place, which requires O-ring seals and may leak under certain conditions. Existing fixtures also do not allow the TO can packages to be easily unloaded, which may result in damage to the package.